Field of the Invention
The present invention relates to a three-dimensional shape measurement apparatus, a three-dimensional shape measurement method and a three-dimensional shape measurement program.
Discussion of the Background
Non patent literature 1 describes an example of a technique in which a three dimensional shape model of an object is generated based on a plurality of two dimensional images including the object captured by moving an imaging unit. According to the three dimensional shape measurement system described in NPL 1, a three dimensional shape mode of an object is generated as follows. First, a moving image of a whole object is captured by moving a stereo camera included in the imaging unit. Here, the stereo camera is also referred to as a both-eye stereoscopic vision camera, serving as an apparatus that captures images of the object from a plurality of viewpoints. Subsequently, at every predetermined frame, three-dimensional coordinate values corresponding to respective pixels are calculated based on a pair of two dimensional images. The three-dimensional values calculated at this time are expressed by a plurality of three-dimensional coordinate values which are different from each other depending on each viewpoint of the stereo camera. Accordingly, in the three-dimensional shape measurement system described in NPL1, feature point group included in a plurality of two dimensional images captured as a moving image is tracked over a plurality of frames, whereby movement of the view point of the stereo camera is estimated. Then, three-dimensional shape models expressed with a plurality of coordinate systems, based on the estimation result of the movement of the view point, are integrated to the same coordinate system so that the three-dimensional shape model of the object is generated.
In NPL2, an example of a technique is described in which a three-dimensional model of an object is generated based on a plurality of depth images (also referred to as distance image or the like) acquired while an infrared depth sensor (hereinafter referred to as imaging unit) is moved. The depth image is an image where distance information about the measured object (information about the distance between the imaging unit and the object) is expressed in pixel units. According to a three-dimensional shape measurement system described in NPL 2, the infrared depth sensor is configured of an infrared projection unit, an infrared imaging unit and a signal processing unit. The infrared projection unit projects a random speckle pattern onto the object, and the infrared imaging unit captures reflected light reflected at the object. Then, the signal processing unit calculates the distance information about the object based on a deviation and a change in the shape of the random speckle pattern captured by the infrared imaging unit and generates depth images. The configuration or the like of this infrared depth sensor is described in PTL 1 to PTL 3 for example.    PTL 1: JP-A-2011-527790    PTL 2: JP-A-2009-511897    PTL 3: JP-A-2009-530604    PTL 4: JP-A-2008-328367 (published as JP-A-2010-152535)    NPL 1: Hiroki Unten, Tomohito Masuda, Tohru Mihashi and Makoto Ando, A practical VR-model generation method by utilizing moving-shots with stereo camera: Stereo Moving-shot Modeling System (SM2S)-, The Virtual Reality Society of Japan, Journal Vol. 12, No. 2, 2007    NPL 2: Shahram Izadi, David Kim, Otmar Hilliges, David Molyneaux, Richard Newcombe, Pushmeet Kohli, Jamie Shotton, Steve Hodges, Dustin Freeman, Andrew Davison, and Andrew Fitzgibbon, “KinectFusion: Real-time 3D Reconstruction and Interaction Using a Moving Depth Camera,” October 2011, Publisher: ACM Symposium on User Interface Software and Technology, (searched on Apr. 15, 2013), internet address <URL: http://research.microsoft.com/apps/pubs/default.aspx?id =1554 16>